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Clostridium botulinum C3 Toxin for Selective Delivery of Cargo into Dendritic Cells and Macrophages. Toxins (Basel) 2022; 14:toxins14100711. [DOI: 10.3390/toxins14100711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/13/2022] [Accepted: 10/14/2022] [Indexed: 11/16/2022] Open
Abstract
The protein toxin C3bot from Clostridium botulinum is a mono-ADP-ribosyltransferase that selectively intoxicates monocyte-derived cells such as macrophages, osteoclasts, and dendritic cells (DCs) by cytosolic modification of Rho-A, -B, and -C. Here, we investigated the application of C3bot as well as its non-toxic variant C3botE174Q as transporters for selective delivery of cargo molecules into macrophages and DCs. C3bot and C3botE174Q facilitated the uptake of eGFP into early endosomes of human-monocyte-derived macrophages, as revealed by stimulated emission depletion (STED) super-resolution microscopy. The fusion of the cargo model peptide eGFP neither affected the cell-type selectivity (enhanced uptake into human macrophages ex vivo compared to lymphocytes) nor the cytosolic release of C3bot. Moreover, by cell fractionation, we demonstrated that C3bot and C3botE174Q strongly enhanced the cytosolic release of functional eGFP. Subsequently, a modular system was created on the basis of C3botE174Q for covalent linkage of cargos via thiol–maleimide click chemistry. The functionality of this system was proven by loading small molecule fluorophores or an established reporter enzyme and investigating the cellular uptake and cytosolic release of cargo. Taken together, non-toxic C3botE174Q is a promising candidate for the cell-type-selective delivery of small molecules, peptides, and proteins into the cytosol of macrophages and DCs.
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Lee CF, Carley RE, Butler CA, Morrison AR. Rac GTPase Signaling in Immune-Mediated Mechanisms of Atherosclerosis. Cells 2021; 10:2808. [PMID: 34831028 PMCID: PMC8616135 DOI: 10.3390/cells10112808] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/15/2021] [Accepted: 10/17/2021] [Indexed: 11/17/2022] Open
Abstract
Coronary artery disease caused by atherosclerosis is a major cause of morbidity and mortality around the world. Data from preclinical and clinical studies support the belief that atherosclerosis is an inflammatory disease that is mediated by innate and adaptive immune signaling mechanisms. This review sought to highlight the role of Rac-mediated inflammatory signaling in the mechanisms driving atherosclerotic calcification. In addition, current clinical treatment strategies that are related to targeting hypercholesterolemia as a critical risk factor for atherosclerotic vascular disease are addressed in relation to the effects on Rac immune signaling and the implications for the future of targeting immune responses in the treatment of calcific atherosclerosis.
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Affiliation(s)
- Cadence F. Lee
- Ocean State Research Institute, Inc., Providence VA Medical Center, Research (151), 830 Chalkstone Avenue, Providence, RI 02908, USA; (C.F.L.); (R.E.C.); (C.A.B.)
- Alpert Medical School, Brown University, Providence, RI 02912, USA
| | - Rachel E. Carley
- Ocean State Research Institute, Inc., Providence VA Medical Center, Research (151), 830 Chalkstone Avenue, Providence, RI 02908, USA; (C.F.L.); (R.E.C.); (C.A.B.)
- Alpert Medical School, Brown University, Providence, RI 02912, USA
| | - Celia A. Butler
- Ocean State Research Institute, Inc., Providence VA Medical Center, Research (151), 830 Chalkstone Avenue, Providence, RI 02908, USA; (C.F.L.); (R.E.C.); (C.A.B.)
- Alpert Medical School, Brown University, Providence, RI 02912, USA
| | - Alan R. Morrison
- Ocean State Research Institute, Inc., Providence VA Medical Center, Research (151), 830 Chalkstone Avenue, Providence, RI 02908, USA; (C.F.L.); (R.E.C.); (C.A.B.)
- Alpert Medical School, Brown University, Providence, RI 02912, USA
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Harre J, Heinkele L, Steffens M, Warnecke A, Lenarz T, Just I, Rohrbeck A. Potentiation of Brain-Derived Neurotrophic Factor-Induced Protection of Spiral Ganglion Neurons by C3 Exoenzyme/Rho Inhibitor. Front Cell Neurosci 2021; 15:602897. [PMID: 33776650 PMCID: PMC7991574 DOI: 10.3389/fncel.2021.602897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 02/19/2021] [Indexed: 11/17/2022] Open
Abstract
Preservation of the excitability of spiral ganglion neurons (SGN) may contribute to an improved speech perception after cochlear implantation. Thus, the application of exogenous neurotrophic factors such as the neurotrophin brain-derived neurotrophic factor (BDNF) to increase SGN survival in vitro and in vivo is a promising pharmacological approach in cochlear implant (CI) research. Due to the difficult pharmacokinetic profile of proteins such as BDNF, there is a quest for small molecules to mediate the survival of SGN or to increase the efficacy of BDNF. The C3 exoenzyme from Clostridium botulinum could be a potential new candidate for the protection and regeneration of SGN. Inhibition of the RhoA GTPase pathway which can be mediated by C3 is described as a promising strategy to enhance axonal regeneration and to exert pro-survival signals in neurons. Nanomolar concentrations of C3, its enzymatically inactive form C3E174Q, and a 26mer C-terminal peptide fragment covering amino acid 156–181 (C3156-181) potentiated the neuroprotective effect on SGN mediated by BDNF in vitro. The neuroprotective effect of C3/BDNF was reduced to the neuroprotective effect of BDNF alone after the treatment with wortmannin, an inhibitor of the phosphatidylinositol-3-kinase (PI3K).The exoenzyme C3 (wild-type and enzyme-deficient) and the C3 peptide fragment C3154–181 present novel biologically active compounds for the protection of the SGN. The exact underlying intracellular mechanisms that mediate the neuroprotective effect are not clarified yet, but the combination of BDNF (TrkB stimulation) and C3 exoenzyme (RhoA inhibition) can be used to protect SGN in vitro.
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Affiliation(s)
- Jennifer Harre
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Hannover, Germany.,Cluster of Excellence "Hearing4all" of the German Research Foundation (EXC 2177/1), Hannover, Germany
| | - Laura Heinkele
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Hannover, Germany
| | - Melanie Steffens
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Hannover, Germany
| | - Athanasia Warnecke
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Hannover, Germany.,Cluster of Excellence "Hearing4all" of the German Research Foundation (EXC 2177/1), Hannover, Germany
| | - Thomas Lenarz
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Hannover, Germany.,Cluster of Excellence "Hearing4all" of the German Research Foundation (EXC 2177/1), Hannover, Germany
| | - Ingo Just
- Institute of Toxicology, Hannover Medical School, Hannover, Germany
| | - Astrid Rohrbeck
- Institute of Toxicology, Hannover Medical School, Hannover, Germany
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4
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Bräutigam J, Bischoff I, Schürmann C, Buchmann G, Epah J, Fuchs S, Heiss E, Brandes RP, Fürst R. Narciclasine inhibits angiogenic processes by activation of Rho kinase and by downregulation of the VEGF receptor 2. J Mol Cell Cardiol 2019; 135:97-108. [PMID: 31381906 DOI: 10.1016/j.yjmcc.2019.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 07/22/2019] [Accepted: 08/01/2019] [Indexed: 11/18/2022]
Abstract
The process of angiogenesis is involved in several pathological conditions, such as tumor growth or age-related macular degeneration. Although the available anti-angiogenic drugs have improved the therapy of these diseases, major drawbacks, such as unwanted side effects and resistances, still exist. Consequently, the search for new anti-angiogenic substances is still ongoing. Narciclasine, a plant alkaloid from different members of the Amaryllidaceae family, has extensively been characterized as anti-tumor compound. Beyond the field of cancer, the compound has recently been shown to possess anti-inflammatory properties. Surprisingly, potential actions of narciclasine on endothelial cells in the context of angiogenesis have been neglected so far. Thus, we aimed to analyze the effects of narciclasine on angiogenic processes in vitro and in vivo and to elucidate the underlying mechanism. Narciclasine (100-300 nM) effectively inhibited the proliferation, undirected and directed migration, network formation and angiogenic sprouting of human primary endothelial cells. Moreover, narciclasine (1 mg/kg/day) strongly reduced the VEGF-triggered angiogenesis in vivo (Matrigel plug assay in mice). Narciclasine mediated its anti-angiogenic effects in part by a RhoA-independent activation of the Rho kinase ROCK. Most importantly, however, the compound reduced the de novo protein synthesis in endothelial cells by approx. 50% without exhibiting considerable cytotoxic effects. As a consequence, narciclasine diminished the presence of proteins with a short half-life, such as the VEGF receptor 2, which is the basis for its anti-angiogenic effects. Taken together, our study highlights narciclasine as an interesting anti-angiogenic compound that is worth to be further evaluated in preclinical studies.
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Affiliation(s)
- Jacqueline Bräutigam
- Institute of Pharmaceutical Biology, Faculty of Biochemistry, Chemistry and Pharmacy, Goethe University, Frankfurt, Germany
| | - Iris Bischoff
- Institute of Pharmaceutical Biology, Faculty of Biochemistry, Chemistry and Pharmacy, Goethe University, Frankfurt, Germany
| | - Christoph Schürmann
- Institute for Cardiovascular Physiology, Faculty of Medicine, Goethe University, Frankfurt, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Rhine-Main, Frankfurt, Germany
| | - Giulia Buchmann
- Institute for Cardiovascular Physiology, Faculty of Medicine, Goethe University, Frankfurt, Germany
| | - Jeremy Epah
- Institute for Cardiovascular Physiology, Faculty of Medicine, Goethe University, Frankfurt, Germany
| | - Simone Fuchs
- Institute of Pharmaceutical Biology, Faculty of Biochemistry, Chemistry and Pharmacy, Goethe University, Frankfurt, Germany
| | - Elke Heiss
- Department of Pharmacognosy, University of Vienna, Vienna, Austria
| | - Ralf P Brandes
- Institute for Cardiovascular Physiology, Faculty of Medicine, Goethe University, Frankfurt, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Rhine-Main, Frankfurt, Germany
| | - Robert Fürst
- Institute of Pharmaceutical Biology, Faculty of Biochemistry, Chemistry and Pharmacy, Goethe University, Frankfurt, Germany.
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The Molecular Basis of Toxins' Interactions with Intracellular Signaling via Discrete Portals. Toxins (Basel) 2017; 9:toxins9030107. [PMID: 28300784 PMCID: PMC5371862 DOI: 10.3390/toxins9030107] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 03/02/2017] [Accepted: 03/04/2017] [Indexed: 12/20/2022] Open
Abstract
An understanding of the molecular mechanisms by which microbial, plant or animal-secreted toxins exert their action provides the most important element for assessment of human health risks and opens new insights into therapies addressing a plethora of pathologies, ranging from neurological disorders to cancer, using toxinomimetic agents. Recently, molecular and cellular biology dissecting tools have provided a wealth of information on the action of these diverse toxins, yet, an integrated framework to explain their selective toxicity is still lacking. In this review, specific examples of different toxins are emphasized to illustrate the fundamental mechanisms of toxicity at different biochemical, molecular and cellular- levels with particular consideration for the nervous system. The target of primary action has been highlighted and operationally classified into 13 sub-categories. Selected examples of toxins were assigned to each target category, denominated as portal, and the modulation of the different portal’s signaling was featured. The first portal encompasses the plasma membrane lipid domains, which give rise to pores when challenged for example with pardaxin, a fish toxin, or is subject to degradation when enzymes of lipid metabolism such as phospholipases A2 (PLA2) or phospholipase C (PLC) act upon it. Several major portals consist of ion channels, pumps, transporters and ligand gated ionotropic receptors which many toxins act on, disturbing the intracellular ion homeostasis. Another group of portals consists of G-protein-coupled and tyrosine kinase receptors that, upon interaction with discrete toxins, alter second messengers towards pathological levels. Lastly, subcellular organelles such as mitochondria, nucleus, protein- and RNA-synthesis machineries, cytoskeletal networks and exocytic vesicles are also portals targeted and deregulated by other diverse group of toxins. A fundamental concept can be drawn from these seemingly different toxins with respect to the site of action and the secondary messengers and signaling cascades they trigger in the host. While the interaction with the initial portal is largely determined by the chemical nature of the toxin, once inside the cell, several ubiquitous second messengers and protein kinases/ phosphatases pathways are impaired, to attain toxicity. Therefore, toxins represent one of the most promising natural molecules for developing novel therapeutics that selectively target the major cellular portals involved in human physiology and diseases.
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Cen LP, Liang JJ, Chen JH, Harvey AR, Ng TK, Zhang M, Pang CP, Cui Q, Fan YM. AAV-mediated transfer of RhoA shRNA and CNTF promotes retinal ganglion cell survival and axon regeneration. Neuroscience 2016; 343:472-482. [PMID: 28017835 DOI: 10.1016/j.neuroscience.2016.12.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 12/14/2016] [Accepted: 12/18/2016] [Indexed: 12/09/2022]
Abstract
The aim of the present study was to determine whether adeno-associated viral vector (AAV) mediated transfer of ciliary neurotrophic factor (CNTF) and RhoA shRNA has additive effects on promoting the survival and axon regeneration of retinal ganglion cells (RGCs) after optic nerve crush (ONC). Silencing effects of AAV-RhoA shRNA were confirmed by examining neurite outgrowth in PC12 cells, and by quantifying RhoA expression levels with western blotting. Young adult Fischer rats received an intravitreal injection of (i) saline, (ii) AAV green fluorescent protein (GFP), (iii) AAV-CNTF, (iv) AAV-RhoA shRNA, or (v) a combination of both AAV-CNTF and AAV-RhoA shRNA. Two weeks later, the ON was completely crushed. Three weeks after ONC, RGC survival was estimated by counting βIII-tubulin-positive neurons in retinal whole mounts. Axon regeneration was evaluated by counting GAP-43-positive axons in the crushed ON. It was found that AAV-RhoA shRNA decreased RhoA expression levels and promoted neurite outgrowth in vitro. In the ONC model, AAV-RhoA shRNA by itself had only weak beneficial effects on RGC axon regeneration. However, when combined with AAV-CNTF, AAV-RhoA shRNA significantly improved the therapeutic effect of AAV-CNTF on axon regeneration by nearly two fold, even though there was no significant change in RGC viability. In sum, this combination of vectors increases the regenerative response and can lead to more successful therapeutic outcomes following neurotrauma.
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Affiliation(s)
- Ling-Ping Cen
- Joint Shantou International Eye Center, Shantou University and The Chinese University of Hong Kong, Shantou, PR China.
| | - Jia-Jian Liang
- Joint Shantou International Eye Center, Shantou University and The Chinese University of Hong Kong, Shantou, PR China
| | - Jian-Huan Chen
- Joint Shantou International Eye Center, Shantou University and The Chinese University of Hong Kong, Shantou, PR China
| | - Alan R Harvey
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, WA, Australia
| | - Tsz Kin Ng
- Department of Ophthalmology and Visual Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, PR China
| | - Mingzhi Zhang
- Joint Shantou International Eye Center, Shantou University and The Chinese University of Hong Kong, Shantou, PR China
| | - Chi Pui Pang
- Joint Shantou International Eye Center, Shantou University and The Chinese University of Hong Kong, Shantou, PR China; Department of Ophthalmology and Visual Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, PR China
| | - Qi Cui
- Joint Shantou International Eye Center, Shantou University and The Chinese University of Hong Kong, Shantou, PR China; Department of Ophthalmology and Visual Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, PR China
| | - You-Ming Fan
- Joint Shantou International Eye Center, Shantou University and The Chinese University of Hong Kong, Shantou, PR China; Department of Neurology, Affiliated Hospital of Hubei University for Nationalities, Enshi, PR China.
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7
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Therapeutic effects of the Rho GTPase modulator CNF1 in a model of Parkinson’s disease. Neuropharmacology 2016; 109:357-365. [DOI: 10.1016/j.neuropharm.2016.06.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 05/25/2016] [Accepted: 06/17/2016] [Indexed: 11/23/2022]
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8
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Choi JK, Park SY, Kim KH, Park SR, Lee SG, Choi BH. GM-CSF reduces expression of chondroitin sulfate proteoglycan (CSPG) core proteins in TGF-β-treated primary astrocytes. BMB Rep 2015; 47:679-84. [PMID: 24602609 PMCID: PMC4345512 DOI: 10.5483/bmbrep.2014.47.12.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Indexed: 01/10/2023] Open
Abstract
GM-CSF plays a role in the nervous system, particularly in cases of injury. A therapeutic effect of GM-CSF has been reported in rat models of various central nervous system injuries. We previously showed that GM-CSF could enhance long-term recovery in a rat spinal cord injury model, inhibiting glial scar formation and increasing the integrity of axonal structure. Here, we investigated molecular the mechanism(s) by which GM-CSF suppressed glial scar formation in an in vitro system using primary astrocytes treated with TGF-β. GM-CSF repressed the expression of chondroitin sulfate proteoglycan (CSPG) core proteins in astrocytes treated with TGF-β. GM-CSF also inhibited the TGF-β-induced Rho-ROCK pathway, which is important in CSPG expression. Finally, the inhibitory effect of GM-CSF was blocked by a JAK inhibitor. These results may provide the basis for GM-CSF’s effects in glial scar inhibition and ultimately for its therapeutic effect on neural cell injuries. [BMB Reports 2014; 47(12): 679-684]
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Affiliation(s)
- Jung-Kyoung Choi
- Department of Physiology, Inha University College of Medicine, Incheon 400-712; Department of Science in Korean Medicine, Cancer Preventive Material Development Research Center, College of Korean Medicine, Kyung Hee University, Seoul 130-701, Korea
| | - Sang-Yoon Park
- Department of Science in Korean Medicine, Cancer Preventive Material Development Research Center, College of Korean Medicine, Kyung Hee University, Seoul 130-701, Korea
| | - Kil Hwan Kim
- Department of Physiology, Inha University College of Medicine, Incheon 400-712, Korea
| | - So Ra Park
- Department of Physiology, Inha University College of Medicine, Incheon 400-712, Korea
| | - Seok-Geun Lee
- Department of Science in Korean Medicine, Cancer Preventive Material Development Research Center, College of Korean Medicine, Kyung Hee University, Seoul 130-701, Korea
| | - Byung Hyune Choi
- Department of Advanced Biomedical Sciences, Inha University College of Medicine, Incheon 400-712, Korea
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Koch JC, Tönges L, Michel U, Bähr M, Lingor P. Viral vector-mediated downregulation of RhoA increases survival and axonal regeneration of retinal ganglion cells. Front Cell Neurosci 2014; 8:273. [PMID: 25249936 PMCID: PMC4155783 DOI: 10.3389/fncel.2014.00273] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 08/20/2014] [Indexed: 12/26/2022] Open
Abstract
The Rho/ROCK pathway is a promising therapeutic target in neurodegenerative and neurotraumatic diseases. Pharmacological inhibition of various pathway members has been shown to promote neuronal regeneration and survival. However, because pharmacological inhibitors are inherently limited in their specificity, shRNA-mediated approaches can add more information on the function of each single kinase involved. Thus, we generated adeno-associated viral vectors (AAV) to specifically downregulate Ras homologous member A (RhoA) via shRNA. We found that specific knockdown of RhoA promoted neurite outgrowth of retinal ganglion cells (RGC) grown on the inhibitory substrate chondroitin sulfate proteoglycan (CSPG) as well as neurite regeneration of primary midbrain neurons (PMN) after scratch lesion. In the rat optic nerve crush (ONC) model in vivo, downregulation of RhoA significantly enhanced axonal regeneration compared to control. Moreover, survival of RGC transduced with AAV expressing RhoA-shRNA was substantially increased at 2 weeks after optic nerve axotomy. Compared to previous data using pharmacological inhibitors to target RhoA, its upstream regulator Nogo or its main downstream target ROCK, the specific effects of RhoA downregulation shown here were most pronounced in regard to promoting RGC survival but neurite outgrowth and axonal regeneration were also increased significantly. Taken together, we show here that specific knockdown of RhoA substantially increases neuronal survival after optic nerve axotomy and modestly increases neurite outgrowth in vitro and axonal regeneration after optic nerve crush.
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Affiliation(s)
- Jan Christoph Koch
- Department of Neurology, University Medicine Göttingen Göttingen, Germany
| | - Lars Tönges
- Department of Neurology, University Medicine Göttingen Göttingen, Germany
| | - Uwe Michel
- Department of Neurology, University Medicine Göttingen Göttingen, Germany
| | - Mathias Bähr
- Department of Neurology, University Medicine Göttingen Göttingen, Germany ; Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB) Göttingen, Germany
| | - Paul Lingor
- Department of Neurology, University Medicine Göttingen Göttingen, Germany ; Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB) Göttingen, Germany
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Rohrbeck A, Schröder A, Hagemann S, Pich A, Höltje M, Ahnert-Hilger G, Just I. Vimentin mediates uptake of C3 exoenzyme. PLoS One 2014; 9:e101071. [PMID: 24967582 PMCID: PMC4072758 DOI: 10.1371/journal.pone.0101071] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 06/03/2014] [Indexed: 02/02/2023] Open
Abstract
Clostridium botulinum C3 exoenzyme (C3) selectively inactivates RhoA/B/C GTPases by ADP-ribosylation. Based on this substrate specificity C3 is a well-established tool in cell biology. C3 is taken up by eukaryotic cells although lacking an uptake and translocation domain. Based on different approaches vimentin was identified as membranous C3-interaction partner by mass spectrometry. Vimentin in fact was partly localized at the outer surface of hippocampal HT22 cells and J744A.1 macrophages. Domain analysis identified the rod domain as binding partner of C3. Vimentin was also involved in uptake of C3 as shown by knock down of vimentin in HT22 and J774A.1 cells. The involvement of vimentin in uptake of C3 was further supported by the findings that the vimentin disruptor acrylamide blocked uptake of C3. Vimentin is not only a major organizing element of the intermediate filament network but is also involved in both binding and uptake of C3 exoenzyme.
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Affiliation(s)
- Astrid Rohrbeck
- Institute of Toxicology, Hannover Medical School, Charité-Universitätsmedizin Berlin, Germany
- * E-mail:
| | - Anke Schröder
- Institute of Toxicology, Hannover Medical School, Charité-Universitätsmedizin Berlin, Germany
| | - Sandra Hagemann
- Institute of Toxicology, Hannover Medical School, Charité-Universitätsmedizin Berlin, Germany
| | - Andreas Pich
- Institute of Toxicology, Hannover Medical School, Charité-Universitätsmedizin Berlin, Germany
| | - Markus Höltje
- Center for Anatomy, Functional Cell Biology, Charité-Universitätsmedizin Berlin, Germany
| | - Gudrun Ahnert-Hilger
- Center for Anatomy, Functional Cell Biology, Charité-Universitätsmedizin Berlin, Germany
| | - Ingo Just
- Institute of Toxicology, Hannover Medical School, Charité-Universitätsmedizin Berlin, Germany
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Auer M, Schweigreiter R, Hausott B, Thongrong S, Höltje M, Just I, Bandtlow C, Klimaschewski L. Rho-independent stimulation of axon outgrowth and activation of the ERK and Akt signaling pathways by C3 transferase in sensory neurons. Front Cell Neurosci 2012; 6:43. [PMID: 23087613 PMCID: PMC3468917 DOI: 10.3389/fncel.2012.00043] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 09/23/2012] [Indexed: 11/15/2022] Open
Abstract
Peripheral nerve injury triggers the activation of RhoA in spinal motor and peripheral sensory neurons. RhoA activates a number of effector proteins including the Rho-associated kinase, ROCK, which targets the cytoskeleton and leads to inhibition of neurite outgrowth. Blockade of the Rho/ROCK pathway by pharmacological means improves axon regeneration after experimental injury. C3bot transferase, an exoenzyme produced by Clostridium botulinum, inactivates RhoA by ADP-ribosylation. It has been successfully applied in experimental CNS lesions to facilitate axon regeneration. Up to now it was not investigated thoroughly whether C3bot exerts positive effects on peripheral axon regeneration as well. In the present study, recombinant membrane permeable C3bot produced a small, but significant, axon outgrowth effect on peripheral sensory neurons dissociated from adult dorsal root ganglia (DRG) of the rat. Neuronal overexpression of C3, however, did not enhance axonal growth. Moreover, transfection of plasmids encoding dominant negative RhoA or RhoA specific shRNAs failed to increase axonal growth. Furthermore, we show that the C3bot mutant, C3E174Q, which lacks RhoA inhibitory activity, still stimulates axonal growth. When analyzing possible signaling mechanisms we found that extracellular signal-regulated kinase (ERK) and Akt are activated by C3bot and ERK is induced by the C3E174Q mutant. Upregulation of kinase activities by C3bot occurs significantly faster than inactivation of RhoA indicating a RhoA-independent pathway of action by C3bot. The induction of ERK signaling by C3bot was detected in embryonic hippocampal neurons, too. Taken together, although RhoA plays a central role for inhibition of axon outgrowth by myelin-derived inhibitors, it does not interfere with axonal growth of sensory neurons on a permissive substrate in vitro. C3bot blocks neuronal RhoA activity, but its positive effects on axon elongation and branching appear to be mediated by Rho independent mechanisms involving activation of axon growth promoting ERK and Akt kinases.
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Affiliation(s)
- Maria Auer
- Division of Neuroanatomy, Innsbruck Medical University Innsbruck, Austria
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Rohrbeck A, Kolbe T, Hagemann S, Genth H, Just I. Distinct biological activities of C3 and ADP-ribosyltransferase-deficient C3-E174Q. FEBS J 2012; 279:2657-71. [DOI: 10.1111/j.1742-4658.2012.08645.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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13
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Rotsch J, Rohrbeck A, May M, Kolbe T, Hagemann S, Schelle I, Just I, Genth H, Huelsenbeck SC. Inhibition of macrophage migration by C. botulinum exoenzyme C3. Naunyn Schmiedebergs Arch Pharmacol 2012; 385:883-90. [DOI: 10.1007/s00210-012-0764-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Accepted: 05/15/2012] [Indexed: 11/24/2022]
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14
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Loske P, Boato F, Hendrix S, Piepgras J, Just I, Ahnert-Hilger G, Höltje M. Minimal essential length of Clostridium botulinum C3 peptides to enhance neuronal regenerative growth and connectivity in a non-enzymatic mode. J Neurochem 2012; 120:1084-96. [PMID: 22239108 DOI: 10.1111/j.1471-4159.2012.07657.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
C3 ADP-ribosyltransferase is a valuable tool to study Rho-dependent cellular processes. In the current study we investigated the impact of enzyme-deficient peptides derived from Clostridium botulinum C3 transferase in the context of neuronal process elongation and branching, synaptic connectivity, and putative beneficial effects on functional outcome following traumatic injury to the CNS. By screening a range of peptidic fragments, we identified three short peptides from C3bot that promoted axon and dendrite outgrowth in cultivated hippocampal neurons. Furthermore, one of these fragments, a 26-amino acid peptide covering the residues 156-181 enhanced synaptic connectivity in primary hippocampal culture. This peptide was also effective to foster axon outgrowth and re-innervation in organotypical brain slice culture. To evaluate the potential of the 26mer to foster repair mechanisms after CNS injury we applied this peptide to mice subjected to spinal cord injury by either compression impact or hemisection. A single local administration at the site of the lesion improved locomotor recovery. In addition, histological analysis revealed an increased serotonergic input to lumbar motoneurons in treated compared with control mice. Pull-down assays showed that lesion-induced up-regulation of RhoA activity within the spinal cord was largely blocked by C3bot peptides despite the lack of enzymatic activity.
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Affiliation(s)
- Peter Loske
- Center for Anatomy, Functional Cell Biology, Charité-Universitätsmedizin Berlin, Berlin, Germany
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Dorner MB, Schulz KM, Kull S, Dorner BG. Complexity of Botulinum Neurotoxins: Challenges for Detection Technology. Curr Top Microbiol Immunol 2012. [DOI: 10.1007/978-3-662-45790-0_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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